How to get ascii value of characters stored in an array?

I have a problem, where i need to get the ASCII values of characters that are stored in a character array. Please help me with sufficient details. Thanks in advance.

[Anil Chowdary Tummala]

I need to convert ASCII to string back in Matlab.

I am using this piece of code in Matlab

clc; close all;
my_string='Shift us up!';
%double(my_string);
ascii_codes=double(my_string);
reconstructed_string=native2unicode(ascii_codes,'');

but I should use this piece of code as program for Matlab Function Block in simulink where native2unicode is not supported giving the following errors

Function 'native2unicode' is not supported for code generation. Consider adding coder.extrinsic('native2unicode') at the top of the function to bypass code generation. Function 'MATLAB Function' (#23.31.56), line 4, column 5: "native2unicode(u,'ASCII')" Launch diagnostic report.

Component:MATLAB Function | Category:Coder error

Errors occurred during parsing of MATLAB function 'string2ASCII/MATLAB Function'

Component:MATLAB Function | Category:Coder error

Simulink cannot determine sizes and/or types of the outputs for block 'string2ASCII/MATLAB Function' due to errors in the block body, or limitations of the underlying analysis. The errors might be inaccurate. Fix the indicated errors, or explicitly specify sizes and/or types for all block outputs.

what should I do

Answer 1

[Stephen23]

MATLAB makes this really easy: you can use the double function:

>> str = 'Hello World';
>> double(str)
ans =
    72   101   108   108   111    32    87   111   114   108   100

Or use uint32 for the entire range of characters supported by the MATLAB char type (fixed thank you @Guillaume).

[Adhi]

Thank you sir. It is working now.

[Thamizhthenvalavan Gajendiran]

So thank you for the answer

[Syednoor Sardar]

When the input string has special characters(such as ' " ) copied from a pdf and used in matlab. double(str) generates an ascii value which differs from the definition of ASCII value for Apostrophe Character. Is there a relationship between ASCII value and font style of character?

[Stephen23]

@Syednoor Sardar: most likely the PDF is using any of the many similar characters:

https://en.wikipedia.org/wiki/Apostrophe#Unicode

Many document applications will automatically replace ASCII single quotes or double quotes (written by the user) with other characters, e.g. to produce the correct left and right quotation marks (without the user needing to have left- and right-quotation characters on their keyboard). This feature is known as "Smart quotes":

https://en.wikipedia.org/wiki/Apostrophe#Smart_quotes

Although you write that the quotes are "ASCII", in all likelihood they are Windows1252 or Unicode (just like MATLAB uses).

[Guillaume]

Matlab does not use ASCII (which consists of only 127 characters, several of them non-printable) and very few programs actually use ASCII. PDF files certainly don't use ASCII.

double(charvector) does not give you ASCII values, it gives you UTF16 (or possibly just UCS-2, it's not documented) character codes. For characters that do belong to the ASCII character sets (which is a few punctuation marks, non-diacritic latin letters, and roman numerals) the codes are the same.

Most likely, you don't want ASCII codes anyway, nobody uses that anymore, it's far too limited and indeed if you want UTF16/UCS-2 character codes, you should use double as Stephen answered.

However, if you want the character codes in a particular encoding, then use unicode2native and specify which encoding you want.

codes = unicode2native(yourstring, 'US-ASCII')

will give you ASCII codes. As said, ASCII is very limited, most likely you'll get a lot of 26 character codes which stands for: this character does not exist in ASCII.

You may also be looking to convert the codes to your local character encoding, in which case:

codes = unicode2native(yourstring)  %use OS locale

edit: Correctly mentioned unicode2native in my comment but used native2unicode in my examples

[Guillaume]

@Stephen, you probably meant 'convert to uint32'.

[Mostafa Salah]

codes = native2unicode(yourstring, 'US-ASCII')

is it give me ascii code if i need to convert "MOSTAFA" to ascii code with parity bit can i do it with this code ?

second, it will give me binary code as output from text or char ?

thank you ..

[Guillaume]

%note that I made a mistake in my comment I said to use unicode2native in the text, which is correct
%but wrote native2unicode in the example which is incorrect.
codes = unicode2native(yourstring, 'US-ASCII');

will give you the ASCII character codes of the characters of yourstring which are valid ASCII characters, so you'll get numbers between 0-127.

Parity bits have nothing to do with ASCII codes. Parity bits are normally associated with a transmission protocol (which may indeed use ASCII to encode characters).

It's unclear what you mean by 'binary code'. As said you'll get numbers between 0-127. If you want to convert that to a 'binary' representation you have to do that yourself.

[Rik]

Just a clarification: Matlab uses UTF-16 to encode chars (this is not undocumented, but fairly hidden), so double(char_array) will not work correctly for all characters. The attached function implements the conversion from UTF-16 to UTF-32 (i.e. to the Unicode code points).

str = 'Hi 😱🙂🤿';
double(str) % incorrect result

ans = 1×9

72 105 32 55357 56881 55357 56898 55358 56639

UTF16_to_unicode(str)

ans = 1×6

72 105 32 128561 128578 129343